Motor question

Merry Christmas
Status
Not open for further replies.

Strahan

Senior Member
Location
Watsontown, PA
Not sure if this is the correct place for the thread or not but here we go. I don't have much time.
Asked this question single phase well pump. No controller 240vac being turned on and off with pressure switch which is fed from a breaker. One leg is pulling 9amps next leg is pulling 12amps and current flow on neutral is 4amps. Obviously something is not balanced I suggested checking all connections. Motor came prewired. Also was told the breaker has tripped and been reset multiple times from old motor. I suggested checking breaker any ideas?
 

dbuckley

Senior Member
Thats a bit odd, as a 240V well pump should be fed with just two wires, one from each hot leg, and Kirchoff tells us the current on each leg should be the same. If thats not the case then theres either something other than the pump in the circuit, and in particular something 120V like, or, there is some leakage going on, and the first thing I'd do is megger the pump. Or, given the leak is 4A, maybe just a multimeter betwixt a hot and ground would show the fault.
 

Strahan

Senior Member
Location
Watsontown, PA
Sorry guys! Bone head move not thinking and in a hurry. Obviously there should not be a neutral. A want to be electrician was asking this.
 

Cold Fusion

Senior Member
Location
way north
I've put in only a few submersible well pumps (three I recall), so I don't have a big knowledge bank.

All had a capacitor box up at the top. The pressure switch feeds 1phase, 240V (no neutral) to the cap box. Four wires are run down from the cap box down to the pump motor - three power leads and an egc.

I don't know what the nominal currents are on each lead. If I get home early tonight I'll measure mine.

cf
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
My experience is either a bad motor winding, a nick in a lead going to ground (with high resistance), or a bad connection, usually in the pressure switch. The pressure switch usually only breaks one leg of the 240V, so if there is a high resistance termination there, it causes an imbalance of current between the two legs, especially if measured downstream of the switch.
 

Strahan

Senior Member
Location
Watsontown, PA
Looks like I'm going to have to go out there and see whats going on. I'm trying to help a guy at work and info is a little off. He doesn't know pump manf. but it was bought at big blue it has 1-black, 1-red, 1-green and 1-yellow. Now I'm not sure what the yellow is maybe an internal thermal protector? Anything that may help before I get there would be appreciated.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Looks like I'm going to have to go out there and see whats going on. I'm trying to help a guy at work and info is a little off. He doesn't know pump manf. but it was bought at big blue it has 1-black, 1-red, 1-green and 1-yellow. Now I'm not sure what the yellow is maybe an internal thermal protector? Anything that may help before I get there would be appreciated.
Sounds like you need a capacitor box. I believe what you have is a running winding, a starting winding and a common terminal. This cannot be done with a controller.
 

dkarst

Senior Member
Location
Minnesota
I think the wiring should be red = start, black= run, yellow= common and greeen ground. There are pumps with the start capacitors at the pump but at 50' - 300' down that has some negative consequences so many have caps in control box. I think the control box should energize the start winding for some period of time, then switch to run winding.
 

gndrod

Senior Member
Location
Ca and Wa
Deep well submersible

Deep well submersible

Not sure if this is the correct place for the thread or not but here we go. I don't have much time.
Asked this question single phase well pump. No controller 240vac being turned on and off with pressure switch which is fed from a breaker. One leg is pulling 9amps next leg is pulling 12amps and current flow on neutral is 4amps. Obviously something is not balanced I suggested checking all connections. Motor came prewired. Also was told the breaker has tripped and been reset multiple times from old motor. I suggested checking breaker any ideas?

If this is an older well system, the pressure switch contacts may have pitting. The both 240V legs (2-wire w/gnd) are switched so one contact may be causing the problem. For a better insight on well system hookups, Google Flint & Walling website for their installation instructions. F&W are probably the best in the industry (1868 pumps) along with Franklin motors.

A word of caution if you do not know the mfr brand of pump down in the hole. Some newer motors have flow rate solid state chips that can be zapped by using a megger. rbj
 

Cold Fusion

Senior Member
Location
way north
...I don't know what the nominal currents are on each lead. If I get home early tonight I'll measure mine. ...

Assuming it is a 3w submersible - here is what I have for the control box. Mine is the 1-1/2hp

I didn't get to measure the currents yesterday - should be able to get to it tonight.

cf
 

Cold Fusion

Senior Member
Location
way north
Assuming it was a submersible.
He never said, he just said it was a well pump. Could be a jet pump or even a centrifugal if it's less than 25' deep.
Considering post 7, I'd say an assumption that the pump is a 3W submersible is valid - not certain, just valid:)

cf
 

gndrod

Senior Member
Location
Ca and Wa
Looks like I'm going to have to go out there and see whats going on. I'm trying to help a guy at work and info is a little off. He doesn't know pump manf. but it was bought at big blue it has 1-black, 1-red, 1-green and 1-yellow. Now I'm not sure what the yellow is maybe an internal thermal protector? Anything that may help before I get there would be appreciated.

I missed this comment earlier. The pump you describe is a 240V 3-wire w/gnd and requires a pump motor controller after the 2-wire pressure switch.
 

Strahan

Senior Member
Location
Watsontown, PA
Ok guys! Finnally just got through this mess. Good information is hard to retrieve. It turns out they replaced this 3 wire submersible well pump with a 4 wire that requires a controller. Split phase motor that requires a controller. Should have went and looked at it to begin with.
 
Status
Not open for further replies.
Top